Hydraulically operated clamshell bucket

ABSTRACT

A clamshell bucket has complementary bowl sections pivotally supported from a head. Arms which are welded at one end to the outer edge of a first bowl section extend inwardly over the top of said bowl section where they are connected to the head on the same pivotal connection which connects the bowl section to the head, said arms having extensions. Other arms have one end welded to the outer edge of the second bowl section where they are pivotally connected to the head on the same pivotal connection which connects said second bowl section to the head, said arms having upward extensions in the nature of a bellcrank and there being an equalizer link pivotally connecting said upward extensions with the extensions of the arms for the first bowl section. An obliquely disposed hydraulic cylinder is pivoted on the horizontal axis to the head above the bucket, said cylinder having a piston rod which is pivotally connected to the arms of the first bowl section intermediate their length. Cutting lips at the sides of the bucket are flared downwardly and outwardly in a novel manner, when the bowl sections are open, to facilitate the digging of trenches and the like.

United States Patent Roy 0. Billings 6621 W. Wisconsin Ave., Milwaukee,Wis.

[72] Inventor 53213 [21] Appl. No. 2,860 [22] Filed Jan. 14, 1970 [45]Patented Dec-14,1971

[54] HYDRAULICALLY OPERATED CLAMSHELL [50] Field of Search [56]References Cited UNITED STATES PATENTS 3,413,029 1 1/1968 Donovan 294/702,007,704 7/1935 Botten..... 37/186 3,103,753 9/1963 Takacs 37/187Primary Examiner-Harvey C. Hornsby Assistant Examiner-Merle F. MafieiAttorney-Morsell & Morsell ABSTRACT: A clamshell bucket hascomplementary bowl sections pivotally supported from a head. Arms whichare welded at one end to the outer edge ofa first bowl section extendinwardly over the top of said bowl section where they are connected tothe head on the same pivotal connection which connects the bowl sectionto the head, said arms having extensions. Other arms have one end weldedto the outer edge of the second bowl section where they are pivotallyconnected to the head on the same pivotal connection which connects saidsecond bowl section to the head, said arms having upward extensions inthe nature of a bellcrank and there being an equalizer link pivotallyconnecting said upward extensions with the extensions of the arms forthe first bowl section. An obliquely disposed hydraulic cylinder ispivoted on the horizontal axis to the head above the bucket, saidcylinder having a piston rod which is pivotally connected to the arms ofthe first bowl section intermediate their length. Cutting lips at thesides of the bucket are flared downwardly and outwardly in a novelmanner, when the bowl sections are open, to facilitate the diggingoftrenches and the like.

PATENTEU DEC I '1 I97! SHEET 1 OF 4 INVENTOR ROY O. BILLINGS ATTORNEYSPATENTED 050141971 SHEET 2 BF 4 INVENTOR ROY 0. Bl LLI NGS ATTORNEYSINVENTOR 30v 0. Bl LLI NGS ATTORNEYS INVENTOR ROY O. BILLINGS bK fATTORNEYS PATENTED DEC 1 4 I97! SHEET [1F 4 I I J I BACKGROUND OF THEINVENTION 1. Field of the Invention The improved clamshell bucket isadapted for use in the smaller sizes of earth-moving machines, and isparticularly useful in excavators of the type having a dip stick or thelike for supporting the bucket.

2. Description of the Prior Art In my U.S. Pat. No. 3,143,228 aclamshell bucket is disclosed wherein there is an hydraulic cylinder foreach bowl member which controls the opening and closing movement. Wherethere are two hydraulic cylinders there is the possibility of hosesbecoming tangled resulting from the necessity of having hydraulic hosesfor each cylinder. Also, where there is an hydraulic cylinder for eachbowl there is no assurance that the opening and closing movement of thetwo bowl sections will be equal, and there is a tendency to twist thebowls because the pressures are applied off center. In my copendingapplication, Ser. No. 839,372, filed July 7, 1969, there is disclosed aconstruction having a single hydraulic cylinder for operating both bowlsections of the bucket. This type of construction is very suitable forlarger sized buckets but it requires a fairly long hydraulic stroke anda substantial amount of oil. Bevin U.S. Pat. No. 2,755,946 discloses anhydraulically operated clamshell bucket wherein there is a singlehydraulic cylinder assembly. However, here the cylinder is verticallydisposed and it digs on the retraction of the cylinder rather than onthe extension stroke, which is undesirable. Furthermore, in Bevin, withthe vertical disposition of the hydraulic assembly, a great deal ofheadroom is required in operation due to the increased height of thebucket assembly when there is a cylinder projecting verticallythereabove. Also, a high bucket assembly tends to tip when pressure isapplied from above, as is contemplated with the present invention.

SUMMARY OF THE INVENTION The present invention comprises a clamshellbucket having complementary bowl sections pivotally supported from ahead which has spaced depending legs. An obliquely disposed hydrauliccylinder is pivoted on trunnions between the legs of the head and hasits piston rod pivotally connected with the top of one of the bowlsections. Connections including an equalizer link operatively connectone bowl section with the other to cause both bowl sections to operateequally. In addition, the cutting lips at the sides of the bowl haveportions which are flared downwardly and outwardly.

It is a general object of the present invention to provide an improvedclamshell bucket wherein both bowl sections are operated by a singlehydraulic cylinder supported obliquely by the head in a manner toprovide for fast, efficient digging action on the extension stroke ofthe hydraulic cylinder assembly while employing a relatively shortstroke with a minimum requirement for hydraulic fluid.

A further object of the invention is to provide a clamshell bucket inwhich there is a special equalizer link connection between the bowlsections, producing a mechanical advantage in operating that bowlsection which is opposite the one to which the hydraulic cylinderassembly is directly connected.

A further object of the invention is to provide an improved clamshellbucket operated by a single hydraulic cylinder wherein there is improvedmeans for causing both bowls to open and close uniformly and in perfecttiming.

A further object of the invention is to provide an improved clamshellbucket in which portions of the cutting lips at the sides of the bowlsections are flared downwardly and outwardly in a novel manner, when thebowls are open, to provide efficient operation when digging trenches orthe like.

A further object of the invention is to provide a bucket which has arelatively low outline so that it can be used in restricted locationsunder sidewalks or foundations, or to undercut a trench, and so thatpressure can be applied from above during the digging cycle withoutcausing the bucket to tip over.

With the above and other objects in view, the invention consists of theimproved hydraulically operated clamshell bucket, and all of its partsand combinations, as set forth in the claims, and all equivalentsthereof.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings,illustrating one complete embodiment of a preferred form of theinvention, in which the same reference numerals designate the same partsin all of the views:

FIG. 1 is a side elevational view of the clamshell bucket with the bowlsin closed condition;

FIG. 2 is a similar view showing the bowls in open condition, partsbeing broken away and shown in section;

FIG. 3 is a fragmentary sectional view taken on the line 3- 3 of FIG. 2;

FIG. 4 is a fragmentary elevational view looking at the end of one ofthe bowl sections;

FIG. 5 is an end view of the bucket while in closed condition; and

FIG. 6 is a sectional view taken approximately on the line 6-6 of FIG.1.

DESCRIPT ION OF THE PREFERRED EMBODIMENTS Referring more particularly tothe drawings, the bucket assembly includes an inverted U-shapedsupporting head 28 having a top deck 29 by means of which it issupported from the end of the dipper stick of an earth moving devicesuch as is illustrated in my copending application, Ser. No. 839,372.The deck has spaced depending legs 27.

THE BOWLS The bucket assembly includes complementary bowl sections 30and 31. Arms 32 positioned over the top of the bowl section 30 haveouter ends welded or otherwise suitably secured to the outer edge of thebowl section as at 33. A pivot pin 34 extends through the upperprojecting ends of the cutting lips 35 (referring to FIG. 1) at oppositesides of the bowl section 30, rotatably through the lower ends of thelegs 27, and through the arms 32, the bucket being preferably fast onthe ends of the pin 34. The arms 32 have lever extensions 36 whichproject inwardly beyond the pivot 34.

Arms 37 positioned over the top of the bowl section 31 have outer endswelded or otherwise suitably secured to the outer edge of the bowlsection, as at 38. A pivot pin 39 extends through upper ends of thecutting lips 40 on opposite sides of the bowl section 31, rotatablythrough the lower ends of the legs 27, and through the inner ends of thearms 37, the ends of the pin 39 being fast to the bowl sections. Thearms 37 have upward lever extensions 41 (referring to FIG. I) so thatthe arms are in the nature of bell cranks. An equalizer link 42 has oneend pivotally connected between the upper ends of the extensions 41 ofthe arms 37 and its other end pivotally connected between the extensions36 of the arms 32.

Mounted for pivotal movement on a pin 43, which extends between the legs27 of the head, is a double-acting hydraulic cylinder 44 which normallyassumes an angular position as shown in FIGS. 1 and 2. The cylinder hasa piston rod 45 which projects angularly downwardly and has an outer endsleeve 45' through which a pin 46 rotatably extends, the sleeve beingpositioned between the arms 32.

As shown more clearly in FIG. 2, the cutting lips 35 and 40 of the bowlsections on each side have triangular portions 47 and 48 which are bentoutwardly on oblique lines 49 and 50 to produce the flare shown in FIGS.3 and 4. Each of these triangularly shaped flared portions 47 and 48 hasone side formed by the line of bend 49 or 50, one side formed by thecutting edge, and the third side formed by the end 52 of the cuttinglip, i.e., the end which is most remote from the pivot 34 or 39. Thisflare may be in any desired amount, but is preferably about 1 inch atthe maximum near the lower outer comers of the cutting lips 47 and 48(assuming the bowl sections are open). These outwardly flared cuttinglips have cutting edges 51 as shown in FIGS. 3 and 4. The lower cornerof each flared portion 47 or 48 projects outwardly at least an inchfarther than any other portion of the bucket side. Thus clearance isprovided when digging a trench, rendering such digging action much moreeffective as there is a minimum of friction in moving the bucket in andout of the trench and while digging. Heretofore, it has been considerednecessary to use side cutting teeth, like the end teeth 53, when it hasbeen attempted to do digging with a clamshell bucket. With the novelflared portions 47. and 48 the necessity of using side teeth iseliminated.

OPERATION Clamshell buckets are customarily used for carrying. Thepresent clamshell bucket, however, can dig as well as carry, and,therefore, is superior to the backhoe for many types of work. Whenoperating the bucket while it is in the open position of FIG. 2, it canbe lowered into the trench or other location and then the piston rod 45is caused to be hydraulically extended. This produces closing movementof the bowl sections during the extension movement of the piston rod.During such closing movement the usual end teeth 53 perform a diggingaction and the special outwardly flared edges of the cutting lips 47 and48 also aid in the digging action, During extension of the piston rod 45the equalizer link 42 acts to cause equal movement of the other bowlsection 31. Due to the particular arrangement of the arms 32 and 37together with the equalizer link 32, the bowls are caused to open andclose uniformly and with perfect timing. The particular linkagearrangement produces a mechanical advantage so that the bowls arecapable of powerful digging action.

With this particular arrangement a single relatively inexpensive shortstroke cylinder, with minimum oil requirements, may be employed forpowering both bowl sections while producing a fast efficient diggingaction.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

What I claim is:

l. A clamshell bucket comprising a supporting head, complementary bowlsections, each having side cutting edges which meet along a generallyupright line when the bucket is closed, one of said bowl sections havingthose upper corners which are nearest said upright line of meetingbetween the bowl sections pivotally connected to the head on atransverse pivot axis, and the other of said bowl sections having itsupper comers which are nearest said upright line of meeting pivotallyconnected to the head on a transverse pivot axis which is spaced fromand parallel with said first pivot axis, the major portion of each bowlsection projecting laterally beyond its pivot axis with the head andhaving an outer upper edge spaced laterally outwardly from and extendingin the same general direction as said pivot axis, the improvementcomprising an obliquely disposed fluid pressure operated cylinder forone of said bowl sections only pivotally supported by said head on atransverse pivot axis and having an extensible piston rod which ispivotally connected to the top of said one bowl section between theouter edge of said bowl section and its pivot axis and a substantialdistance below the pivotal connection between the cylinder and head whenthe bowl sections are closed, said piston rod being extended when thebowl sections are closed, and means for causing operation of the otherbowl section including an equalizer link connecting said first bowlsection with said other bowl section for transmitting operating movementthereto, said means and link being the sole means for operating saidother bowl section and being disposed and arranged to cause equalmovement of the two bowl sections when the cylinder is operated, therebeing an arm rigidly connected to and extending from the outer edge ofone bowl section over the top of said section and having an extensionwhich projects inwardly beyond the pivotal connection between said bowlsection and the head and the piston rod being pivotally connected tosaid arm intermediate its length, there a so being an arm extendinginwardly from the outer edge over the top of the other bowl section andrigidly connected thereto and having an extension which projects fromthe pivotal connection between said last-mentioned bowl section and thehead, and the equalizer link being pivotally connected at one end to thelast-mentioned extension and at the other end to the the lastmentionedextension and at the other end to the inward extension of the arm of thefirst bowl section, with said last pivotal connection being intermediatethe pivotal connections between the two bowl sections and the head.

t t '0 t i

1. A clamshell bucket comprising a supporting head, complementary bowlsections, each having side cutting edges which meet along a generallyupright line when the bucket is closed, one of said bowl sections havingthose upper corners which are nearest said upright line of meetingbetween the bowl sections pivotally connected to the head on atransverse pivot axis, and the other of said bowl sections having itsupper corners which are nearest said upright line of meeting pivotallyconnected to the head on a transverse pivot axis which is spaced fromand parallel with said first pivot axis, the major portion of each bowlsection projecting laterally beyond its pivot axis with the head andhaving an outer upper edge spaced laterally outwardly from and extendingin the same general direction as said pivot axis, the improvementcomprising an obliquely disposed fluid pressure operated cylinder forone of said bowl sections only pivotally supported by said head on atransverse pivot axis and having an extensible piston rod which ispivotally connected to the top of said one bowl section between theouter edge of said bowl section and its pivot axis and a substantialdistance below the pivotal connection between the cylinder and head whenthe bowl sections are closed, said piston rod being extended when thebowl sections are closed, and means for causing operation of the otherbowl section including an equalizer link connecting said first bowlsection with said other bowl section for transmitting operating movementthereto, said means and link being the sole means for operating saidother bowl section and being disposed and arranged to cause equalmovement of the two bowl sections when the cylinder is operated, therebeing an arm rigidly connected to and extending from the outer edge ofone bowl section over the top of said section and having an extensionwhich projects inwardly beyond the pivotal connection between said bowlsection and the head and the piston rod being pivotally connected tosaid arm intermediate its length, there also being an arm extendinginwardly from the outer edge over the top of the other bowl section andrigidly connected thereto and having an extension which projects fromthe pivotal connection between said last-mentioned bowl section and thehead, and the equalizer link being pivotally connected at one end to thelast-mentioned extension and at the other end to the inward extension ofthe arm of the first bowl section, with said last pivotal connectionbeing intermediate the pivotal connections between the two bowl sectionsand the head.